The effects of an increase in 10 µg·m−3 in pollutant concentration on symptoms of irritation on days on which no steroid was used
| Lag days | Incident episodes | Prevalent episodes | |
| Eye irritation | |||
| O3 | 0 | 1.12 (0.98–1.29)# | 1.06 (0.90–1.24) |
| 0–2 | 1.17 (0.64–2.16) | 1.34 (0.96–1.87)# | |
| 0–4 | 1.09 (0.71–1.69) | 1.31 (1.08–1.60)* | |
| PM | 0 | 1.07 (0.66–1.71) | 1.20 (0.88–1.65) |
| 0–2 | 0.83 (0.45–1.53) | 1.71 (0.97–3.01) | |
| 0–4 | 0.92 (0.46–1.83) | 1.97 (1.03–3.76)* | |
| Throat irritation | |||
| O3 | 0 | 1.11 (0.84–1.46) | 1.05 (0.96–1.16) |
| 0–2 | 1.36 (1.08–1.73)* | 1.11 (0.99–1.25)# | |
| 0–4 | 1.22 (0.72–2.07) | 1.07 (0.85–1.36) | |
| PM | 0 | 1.33 (0.66–2.69) | 1.23 (0.83–1.82) |
| 0–2 | 1.28 (0.58–2.80) | 1.08 (0.68–1.73) | |
| 0–4 | 1.06 (0.38–2.95) | 0.91 (0.47–1.73) | |
| Nose irritation | |||
| O3 | 0 | 1.05 (0.83–1.32) | 1.09 (1.00–1.20)* |
| 0–2 | 1.24 (1.0–1.54)* | 1.27 (1.06–1.52)* | |
| 0–4 | 1.16 (1.0–1.35)* | 1.15 (1.02–1.29)* | |
| PM | 0 | 0.74 (0.48–1.13) | 1.20 (0.91–1.58) |
| 0–2 | 0.76 (0.42–1.36) | 1.09 (0.78–1.52) | |
| 0–4 | 0.96 (0.53–1.73) | 1.09 (0.73–1.61) |
Data are presented as odds ratios (95% confidence intervals)
Each odds ratio was obtained with a generalised estimating equations logistic model, adjusted for the effects of time trend, day of the week, weather and pollen levels. Models without interaction terms, results of those including interaction terms are given in the text
O3: ozone
PM: particles with an aerodynamic diameter of <13 µm
#: 0.05<p<0.10
*: p<0.05